(1) Field of the Invention
The present invention relates to adhesive sheets for proctecting against aquatic growths, such as animal and plant growths, which attach and propagate on the surface of ships and other structures in contact with water.
(2) Description of the Prior Art
Usually, on the surface of ships and other underwater structures, animals such as barnacles, mussels, oysters, pearl-oysters and the like, as well as plants such as various kinds of seaweeds and the like, will attach themselves and propagate along the surface. Such animal and plant growths impede navigation and promote deterioration of the surface and, therefore, various measures have been taken to prevent the adhesion and propagation of these animals and plants. For example, there has been proposed a method of applying paint containing a poisonous substance which slowly dissolves in small amounts in sea water; however, this method is disadvantageous because the paint must be recoated every 1-2 years to continue the effect of preventing the adhesion. Also, a method for preventing the adhesion of noxious animals and plants by using copper plate is known; however, since the chemical reaction between copper and sea water proceeds comparatively comparatively rapidly, this method, suffers the drawback of durability unless a fairly thick copper plate is used. Consequently, this method is not practical from a commercial point of view.